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kichikuou_xsystem35-sdl2/src/cache.c
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2019-01-06 14:57:56 +09:00

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C

/*
* cache.c general cache manager
*
* Copyright (C) 1997-1998 Masaki Chikama (Wren) <chikama@kasumi.ipl.mech.nagoya-u.ac.jp>
* 1998- <masaki-c@is.aist-nara.ac.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* $Id: cache.c,v 1.5 2003/07/21 23:06:47 chikama Exp $ */
#include "config.h"
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
#include "portab.h"
#include "cache.h"
/* maximum cache size (in MB) */
#ifndef CACHE_TOTALSIZE
#define CACHE_TOTALSIZE 20
#endif
static int totalsize; /* total size in cache */
static int dummyfalse = 0; /* dummy in_use flag */
static int dummytrue = 1; /* dummy in_use flag */
/*
* static methods
*/
static void remove_in_cache(cacher *id);
/*
* Remove data in cache
* id: cache handler
*/
static void remove_in_cache(cacher *id) {
cacheinfo *ip = id->top;
cacheinfo *ic = ip->next;
if (!ic)
return;
while(ic->next != NULL) {
if (!*ic->in_use) {
totalsize -= ic->size;
ip->next = ic->next;
id->free_(ic->data);
free(ic);
} else {
ip = ic;
}
ic = ip->next;
}
return;
}
/*
* Create new cache object
* delcallback: callback function for delete cache data object
* return: new cache handler
*/
cacher *cache_new(void *delcallback) {
cacher *c = calloc(1, sizeof(cacher));
c->top = calloc(1, sizeof(cacheinfo));
c->top->next = NULL;
c->top->in_use = &dummytrue;
c->free_ = delcallback;
return c;
}
/*
* Insert data to cache
* id : cache handler
* key : data key
* data : data to be cached
* size : data size
* in_use: in_use mark pointer, if in_use is nonzero, dont remove from cache
*/
void cache_insert(cacher *id, int key, void *data, int size, int *in_use) {
cacheinfo *i = id->top;
if (CACHE_TOTALSIZE <= (totalsize >> 20)) {
remove_in_cache(id);
}
while(i->next != NULL) {
i = i->next;
}
i->key = key;
i->data = data;
i->size = size;
i->next = calloc(1, sizeof(cacheinfo));
i->next->next = NULL;
if (in_use) {
i->in_use = in_use;
} else {
i->in_use = &dummyfalse;
}
totalsize += size;
}
/*
* Search data in cache
* id : cache handler
* key: data search key
* return: pointer to cached data
*/
void *cache_foreach(cacher *id, int key) {
cacheinfo *i = id->top;
while(i != NULL) {
if (i->key == key) {
return i->data;
}
i = i->next;
}
return NULL;
}